Should Tahiyyat-ul-Masjid be offered on Fridays?

Q 7: Is it obligatory to offer Tahiyyat-ul-Masjid (two-unit Prayer to salute the mosque) while the Imam (the one who leads congregational Prayer) is delivering the Friday Khutbah (sermon)? Is it permissible to delay the `Isha' (Night) Prayer until after midnight, for example until two o'clock in the morning? A: Firstly, it is permissible for those who enter the Masjid to offer Tahiyyat-ul-Masjid before sitting down, that is, as soon as they enter the Masjid. This is permissible while the Imam is delivering the Khutbah. With respect to this, it was related on the authority of Jabir (may Allah be pleased with him) in the Two Sahih (authentic) Books of Hadith (i.e. Al-Bukhari and Muslim) that he reported: A man entered the Masjid while the Prophet (peace be upon him) was delivering the Friday Khutbah. The Prophet (peace be upon him) said to him, "Have you prayed?" The man replied in the negative. The Prophet (peace be upon him) said, "Offer two Rak`ahs." Secondly, the time of `Isha' Prayer lasts until midnight, and this is the preferred time. (Part No. 6; Page No. 139

A: Firstly, it is permissible for those who enter the Masjid to offer Tahiyyat-ul-Masjid before sitting down, that is, as soon as they enter the Masjid. This is permissible while the Imam is delivering the Khutbah. With respect to this, it was related on the authority of Jabir (may Allah be pleased with him) in the Two Sahih (authentic) Books of Hadith (i.e. Al-Bukhari and Muslim) that he reported: A man entered the Masjid while the Prophet (peace be upon him) was delivering the Friday Khutbah. The Prophet (peace be upon him) said to him, "Have you prayed?" The man replied in the negative. The Prophet (peace be upon him) said, "Offer two Rak`ahs." Secondly, the time of `Isha' Prayer lasts until midnight, and this is the preferred time. (Part No. 6; Page No. 139) There is a time of necessity - from midnight until the crack of dawn - during which it is not permissible to delay the `Isha' Prayer just as it is not permissible to delay the `Asr (Afternoon) Prayer until the sun turns yellow. However, Salah can be offered during the time of necessity if there is a Shar`y (Islamically lawful) excuse that forces a person to do this, but they have to make Tawbah (repentance to Allah) for delaying it if there is no Shar`y excuse.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.